| abstract |
The compounds of formula (I) are inhibitors of HSP90 activity and are useful in the treatment of proliferative diseases such as cancer [wherein R 1 , R 2 and R 3 are as defined herein. X is —OR 4 or —NR 4 R 5, wherein R 4 and R 5 are independently hydrogen or optionally substituted C 1 -C 6 alkyl, or R 4 and R 5 together with the nitrogen to which they are attached form an optionally substituted nitrogen-containing ring having 5 to 8 ring atoms). |